Reproduction system featuring automatic selection among multiple reproduction modes

ABSTRACT

A video CD has a program area having plural recorded programs and a managemental area in which alternatives for selecting the programs in reproducing the programs are recorded as the managemental information. In the managemental area is pre-recorded an identifier for determining the program reproducing mode as the managemental information. An optical head 34 reproduces the programs from the program area of the video CD, while reproducing the managemental information from the managemental area. A system controller 53 judges the reproducing mode based upon the identifier included in the managemental information and, based upon the judged reproducing mode, selects an alternative based upon the random number if the reproducing mode is the random reproduction mode. The system controller 53 controls the optical head 34 and the servo circuit 37 for reproducing the program associated with the alternative. The audio data of the reproduced program is decoded by am MPEG audio decoder 40 and outputted after conversion into audio signals by a D/A converter 45. The video data is decoded by a video decoder 42 and outputted after conversion into video signals by the D/A converter 47.

TECHNICAL FIELD

This invention relates to a reproducing apparatus and a reproducingmethod for reproducing a program, such as audio data or video data, froma recording medium, and the recording medium. More particularly, itrelates to a recording medium, compact disc (CD) or a video CD, havingthe program reproducing sequences previously recorded thereon, and areproducing apparatus and a reproducing method for reproducing videodata or audio data from the recording medium.

BACKGROUND ART

A wide variety of play-only (so-called ROM) type disc-shaped recordingmedia, such as CD-DA (CD-digital audio), have become widespread. Withthe CD-DA, audio signals are digitized and recorded as audio data so asto be reproduced in order to enable the music or the like to be enjoyedwt a high sound quality. As a sort of this CD-DA, there has also beenknown a CD-G (CD-graphic) in which still picture data is recorded in aso-called sub-code data. There has also been developed a video CD, as asort of the CD-ROM, in which moving picture data (video data) has beenrecorded as audio data.

Some of the video CDs have the so-called playback control function. Theplayback control controls the reproducing operation of a program, suchas audio data or video data, using the list information pre-recorded onthe video CD, and realizes a simplified interactive reproduction.

Specifically, mainly the selection list and the play list are recordedas the list information in the video CD. These lists are of a layeredstructure. The selection list is reproduced from the video CD and themenu based upon the selection list is displayed on a screen of thedisplay section. The user then performs the selecting operationresponsive to the menu screen and selects the play list which is aportion of the selection list. In the play list, there is stated theprogram to be reproduced, such as track numbers. When the play list isselected, the reproducing device reproduces the program stated in theplay list. Basically, by such operation, the video CD may be utilized asa software of the type that permits conversation with the user.

Meanwhile, if a menu is displayed by this playback control on thescreen, the user occasionally does not perform any selective operationresponsive to the displayed menu. In anticipation of such case, the waittime is set in the selection list. Besides, there is recorded therein anoperation which should be executed when the wait time has elapsedwithout any operation being performed. That is, if the time has elapsedwithout any operation being performed, a particular alternative(program) in the selection list may be executed automatically.

There is also known a reproducing apparatus for reproducing a CD (CDplayer) having a random number generator, so that, when the user pressesan operating button commanding random reproduction, the program of anumber corresponding to the random number generated by the random numbergenerator is reproduced.

However, the random reproduction is performed by the user's instruction,that is, it is not performed automatically. Thus, if random reproductionis to be performed in an exhibition of products or a demonstration at aretail store, the user has to press the operating button each timerandom reproduction is made, which inconveniences the user.

On the other hand, the random numbers generated by the random numbergenerator are not necessarily different but the same value may begenerated on end, while the random numbers may be generated in the samesequence for the first run of random numbers and the second run ofrandom numbers, thus giving no fascinating reproducing sequence.

In view of the above-mentioned problem of the prior art, it is an objectof the present invention to provide a recording medium on which isrecorded not only the program of audio data or video data but also thedescriptor or identifier commanding a playback mode of continuousprogram reproduction or random program reproduction.

It is another object of the present invention to provide a reproducingapparatus and a reproducing method whereby the descriptor or identifieris reproduced from a recording medium for automatically performingrandom reproduction and whereby the same program may be prohibited frombeing reproduced twice or more in the course of random reproduction.

DISCLOSURE OF THE INVENTION

A reproducing apparatus for program reproduction from a recording mediumaccording to the present invention has a program area having a pluralityof programs recorded therein and a managemental area having recordedtherein program selecting alternatives for selecting the programs inreproducing the programs, as the managemental information. Themanagemental area of the recording medium has an identifier fordetermining the program reproducing mode pre-recorded therein as themanagemental information. The reproducing apparatus includes reproducingmeans for reproducing the program from the program area of the recordingmedium and for reproducing the managemental information from themanagemental area, judgment means for judging the reproducing mode basedupon the identifier included in the managemental information reproducedby the reproducing means, random number generating means for generatingthe random number, selection means for selecting the alternatives basedupon the random number from the random number generating means if thereproducing mode judged by the judgment means is the randomreproduction, and control means for controlling the reproducing meansfor reproducing the program associated with the alternative selected bythe selection means.

A reproducing apparatus for program reproduction from a recording mediumaccording to the present invention similarly has a program area having aplurality of programs recorded therein and a managemental area havingrecorded therein program selecting alternatives for selecting theprograms in reproducing the programs. The managemental area of therecording medium has an identifier for determining the programreproducing mode and the limit time pre-recorded therein. Thereproducing apparatus includes reproducing means for reproducing theprograms from the program area of the recording medium and forreproducing the managemental information from the managemental area,time measurement means for measuring the limit time included in themanagemental information reproduced by the reproducing means, judgementmeans for judging the reproducing mode based upon the identifierincluded in the managemental information when the limit time of the timemeasurement means exceeds the limit time, random number generating meansfor generating the random number, selection means for selecting thealternatives based upon the random number from the random numbergenerating means if the reproducing mode judged by the judgment means isthe random reproduction, and control means for controlling thereproducing means for reproducing the program associated with thealternative selected by the selection means.

A reproducing method for program reproduction from a recording mediumaccording to the present invention has a program area having a pluralityof programs recorded therein and a managemental area having recordedtherein program selecting alternatives for selecting the programs inreproducing the programs, as the managemental information. Themanagemental area of the recording medium has an identifier fordetermining the program reproducing mode pre-recorded therein as themanagemental information. The reproducing method includes the steps ofreproducing the managemental information from the managemental area andjudging the reproducing mode based upon the identifier included in themanagemental information, selecting an alternative based upon thegenerated random number if the reproducing mode is judged to be a randomreproduction in the judgment step, and reproducing the programassociated with the alternative selected by the selecting step.

A reproducing method for program reproduction from a recording mediumaccording to the present invention similarly has a program area having aplurality of programs recorded therein and a managemental area havingrecorded therein program selecting alternatives for selecting theprograms in reproducing the programs. The managemental area of therecording medium has an identifier for determining the programreproducing mode and the limit time pre-recorded therein. Thereproducing method includes the steps of reproducing the managementalinformation from the managemental area and comparing the limit timeincluded in the management information to a count value of a counter,judging the reproducing mode based upon the identifier included in themanagemental information if the count value is found in the comparisonstep to have exceeded the limit time, selecting an alternative basedupon the generated random number if the reproducing mode is judged to bea random reproduction in the judgment step, and reproducing the programassociated with the alternative selected by the selecting step.

A recording medium according to the present invention has a program areahaving a plurality of programs recorded therein and a managemental areafor managing these plural programs, wherein an identifier foridentifying whether continuous reproduction or random reproduction basedupon random numbers is to be performed by way of program reproduction.

According to the present invention, a program is to be reproduced from arecording medium having a program area having a plurality of programsrecorded therein and a managemental area having program selectingalternatives for selecting the programs in reproducing the recordedprograms. In the managemental area of the recording medium ispre-recorded a identifier for determining the program reproducing mode.The managemental information is reproduced from the managemental areaand the reproducing mode is judged based upon the identifier included inthe managemental information. If the reproducing mode is judged to bethe random reproduction, an alternative is selected based upon thegenerated random number, and the program corresponding to the selectedalternative is reproduced.

According to the present invention, a program is to be reproduced from arecording medium having a program area having a plurality of programsrecorded therein and a managemental area having program selectingalternatives for selecting the programs in reproducing the recordedprograms. In the managemental area of the recording medium, there arepre-recorded an identifier for determining the program reproducing modeand the limit time. The managemental information is reproduced from themanagemental area. The limit time included in the managementalinformation and the count value of a counter are compared to each other.If the count value exceeds the limit time, the reproducing mode isjudged based upon the identifier included in the managementalinformation. If the reproducing mode is judged to be the randomreproduction, an alternative is selected based upon the generated randomnumber and the program associated with the selected alternative isreproduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the format of XA design specifications for a CD-ROM.

FIG. 2 illustrates a picture size of a video CD.

FIGS. 3A, 3B, 3C, 3D, and 3E illustrate video data of a video CD.

FIG. 4 illustrates a track structure of a video CD.

FIGS. 5A, 5B and 5C illustrate a sector construction of a video CD.

FIGS. 6A and 6B illustrate a construction on a disc of a video CD.

FIG. 7 illustrates a disc frame structure.

FIGS. 8A and 8B illustrate a sub-code data structure.

FIGS. 9A and 9B illustrate sub-Q data.

FIG. 10 illustrates TOC data.

FIG. 11 illustrates a directory structure of a video CD.

FIG. 12 illustrates a PVD of the video CD.

FIG. 13 illustrates a video CD information area of a video CD.

FIG. 14 illustrates the disc information of the video CD.

FIG. 15 illustrates a segment play item contents table in the discinformation in the video CD.

FIG. 16 illustrates a list ID offset table of the video CD.

FIG. 17 illustrates a play list of the video CD.

FIG. 18 illustrates the play item number of the video CD.

FIG. 19 illustrates a selection list of the video CD.

FIG. 20 illustrates the wait time until timeout of the video CD.

FIG. 21 illustrates a list structure of the video CD.

FIG. 22 illustrates the playback control operation in the list structureof the video CD.

FIG. 23 shows the appearance of a reproducing apparatus embodying thepresent invention.

FIG. 24 is a block diagram of the reproducing apparatus shown in FIG.23.

FIG. 25 illustrates a list structure for illustrating the randomselecting operation of the reproducing apparatus shown in FIG. 23.

FIG. 26 illustrates another list structure for illustrating the randomselecting operation of the reproducing apparatus shown in FIG. 23.

FIG. 27 is a flow chart for illustrating the processing for realizationof the random selecting operation of the reproducing apparatus shown inFIG. 23.

FIGS. 28A, 28B, 28C, 28D and 28E illustrate a bit map for randomdesignation employed in the random selecting operation of thereproducing apparatus shown in FIG. 23.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the drawings, preferred embodiments of the reproducingmethod and apparatus and the recording medium according to the presentinvention will be explained in detail.

In the present embodiment, the present invention is applied to areproducing apparatus for reproducing audio data or video data frome.g., a compact digital audio (CD-DA), CD-G or video CD. The reproducingapparatus has the so-called playback control (PBC) function for thevideo CD.

The description is made in the following sequence:

I. Data Construction of video CD

1. Data Configuration

a. Video Data

b. Audio Data

c. Management Data

2. Track Structure

3. Sector Construction

4. Arrangement on Disc

5. TOC and Sub-code

6. Directory Construction

7. Video CD Data Track

a. Primary Volume Descriptor (PVC)

b. Video CD Data Track

b1. Disc Information

b2. Entry Table

b3. List ID Offset Table

b4. Play Sequence Descriptor

Play List

Selection List

End List

c. Segment Play Item

II. Playback Control

1. List Construction

2. Illustrative Example

III. Illustrative Construction of Reproducing Apparatus

1. Appearance

2. Specific Circuit Construction

IV. Random Reproducing Operation during PBC Operation

I. Data Construction of video CD

1. Data Configuration

The standard for the video CD describes that video data or audio dataencoded using the Moving Picture Experts Group (MPEG) standardized asthe high efficiency encoding technique be recorded for 60 minutes orlonger on an optical disc in accordance with the so-called CD-ROM formatand the recorded audio data or video data is reproduced from the discfor outputting the video and audio signals of the moving picture. Thusthe optical disc of the video CD standard becomes useful as thehousehold software for music, motion picture or karaoke while being ableto cope with the software for education, electronic publication softwareor game software in combination with still pictures.

The video CD standard prescribes that moving picture data be encoded(compressed) in accordance with the MPEG system, while audio data isencoded with a compression ratio of approximately one-sixth of 1.4 Mbpsfor the usual CD-ROM format, that is 22.4 kbps, for time-divisionalmultiplexed recording of the audio data and the video data on theoptical disc. In addition, managemental data required for reproductionis recorded in a prescribed region.

a. Video Data

FIG. 1 shows the CD-ROM XA format in the video CD.

As the recording format for video and audio data, 1.152 Mbits/sec and 64to 384 kbp/sec are allocated for the video data and for the audio data,respectively, as shown in FIG. 1. The number of pixels of the video datais 352×240 for video signals of the National Television System Committee(NTSC system) (29.97 Hz) and for a film (23.976 Hz), and 352×288 forvideo signals of the Phase Alternation by Line (PAL) System (25 Hz).

On the other hand, the number of pixels for a still picture for the NTSCsystem is 352×240 and 704×480 for the standard level and for the highdefinition level, respectively, while that for the PAL system is 352×288and 704×576 for the standard level and for the high definition level,respectively.

The manner of encoding of video data (moving picture data) in accordancewith the MPEG system for data compression is as follows: Assuming thatthe pre-compression video signals are of the NTSC system, these videosignals are constituted by video signals of 30 frames/sec (or 60field/sec) video signals.

With the MPEG system, video data of e.g., one frame, i.e., one picture,is divided into 22 blocks in the horizontal direction and 15 blocks inthe vertical direction, totalling 330 blocks. The video data of therespective blocks is transformed by discrete cosine transform (DCT) andre-quantized for diminishing the number of bits with high-frequencycomponents of the DCT coefficients being set to zero. The DCTcoefficients of the respective blocks are re-arrayed in a zig-zagfashion, beginning from the DCT coefficients lying at an upper left endof the screen, and are encoded by run-length coding for furtherdiminishing the number of bits.

In the case of pictures of the encoded video signals, picture signals ofpictures temporarily forward and backward a given picture exhibit strongcorrelation. With the MPEG system, this correlation is utilized forfurther compressing the information volume. The MPEG system providesthree picture types having different degrees of picture compression.These three pictures are termed an intra-coded picture (I-picture), apredictive-coded picture (P-picture) and a bi-directionalpredictive-coded picture (B-picture).

In general, thirty frames (pictures) present in one second are arrayedas the I-, P- and B-pictures, as shown for example in FIG. 3A.Specifically, I-pictures I1 and I2 are arranged every 15 frames, whileeight P-pictures P1 to P8 and twenty B-pictures B1 to B20 are alsoarranged. The domain from a given I-picture to the next I-picture istermed a group-of-picture or GOP.

The picture data of the I-picture are generated by DCT of picture datain the picture followed by encoding.

The picture data of the P-picture are generated by motion compensatedencoding based upon the P-picture or I-picture closest thereto. Forexample, the picture data of the P-picture P1 and the picture data ofthe P-picture P2 are generated based upon the I-picture I1 and theP-picture P1, respectively, as shown in FIG. 3B. Thus the P-picture iscompressed to a higher degree than the I-picture. Meanwhile, since theP-picture is formed based upon sequentially temporally forward I- orP-picture, any error produced in the temporally forward basic picture ispropagated to the next following pictures.

The picture data of the B-picture are generated by motion-compensatedpredictive coding based upon both past and future I-or P-pictures. Forexample, the picture data of the B-pictures B1 and B2 are generatedbased upon the I-picture I1 and the P-picture P1, whole the picture dataof the B-pictures B3 and B4 are generated based upon the P-pictures P1and P3. The B-picture is compressed to the utmost extent among the threepicture sorts. Since the B-picture is not used as reference for theremaining pictures, there is no risk of error propagation.

The MPEG algorithm allows for free selection of the positions andperiods of the I-pictures on the part of the manufacturer in view ofvarious circumstances such as random accessing or scene cutting. Ifemphasis is placed on random accessing, at least two I-pictures arerequired in one second, a shown in FIG. 3A.

The frequency of occurrence of the P- and B-pictures may be selectedfreely in dependence upon e.g., the memory capacity of an encoderconfigured for encoding the video data in accordance with the MPEGsystem.

The encoder in the MPEG system is configured for re-arraying a bitstreamof picture data for increasing the decoding efficiency in the decoderbefore outputting the bitstream. For example, the sequence of the framesto be displayed (decoder outputting sequence) is the sequence of theframe numbers, as shown in a lower part of FIG. 3A. However, in orderfor the decoder to re-synthesize a B-picture, the temporally backwardP-picture, as a reference picture, is required at the time point ofdecoding of the B-picture. Thus the encoder re-arrays the frame sequenceshown in FIG. 3D so that the P-picture P1 lies ahead of the B-pictureB1, and the resulting picture array is transmitted as a bitstream of thepicture data, as shown for example in FIG. 3E.

b. Audio Data

The MPEG audio data format accommodates a wide range of the encodingrates ranging from 32 kbit/sec to 44 kbit/sec. However, for ease inpreparation of the software and improvement in the sound quality, theencoding rate for moving pictures for tracks #2 ff. is set to 224kbit/sec. The sampling frequency is 44.1 kHz, as in the case of theCD-DA.

c. Managemental Data

In addition to the programs for video data and audio data, managementaldata managing control of various control operations for the reproducingoperations are recorded on the video CD.

That is, as in the case of the CD-DA, the table-of-contents (TOC) andthe sub-code are recorded for specifying e.g., the number of tracks(programs) and the absolute time specifying the start position of eachtrack.

With the video CD, the track #1 is used as a video CD data track forrecording various managemental information items, as will be explainedsubsequently. The playback control operation as later explained is alsoimplemented using data present in the video CD data tracks. Thesemanagemental data will be explained subsequently.

2. Track Structure

FIG. 4 shows the data structure of a track on which is recordedprogram-based video data and audio data of e.g., a motion picture.

In anticipation of a retrieval by a track number, as in the case of theCD-DA, a 150-sector pause margin is provided at the leading end of thetrack. The pause margin is followed by a 15-sector front margin. Thelast 15 sectors of the track constitute a rear margin, which is a vacantdata region.

The space between the front margin and the rear margin is the MPEG dataregion in which is recorded data encoded in accordance with the encodingrule consistent with the MPEG system. In the MPEG region are arrayedsectors V having video data recorded therein and sectors A having audiodata recorded therein at a ratio of 6:1 on an average, as shown in FIG.4. That is, the interleaved video and audio data are recorded withtime-divisional multiplexing in the MPEG data region.

3. Sector Construction

FIG. 5 shows the construction of a sector as a data unit in a track.

FIG. 5A shows the basic sector construction. Each sector is formed by apack made up of a pack header and packet data.

Specifically, a 12-byte pack header is provided at the leading end of asector, with the remaining 2312 bytes making up a packet.

In the pack header is arrayed a 4-byte pack start code, followed by a5-byte system clock reference (SCR) and a 3-byte trailing end MUX ratein this order.

The system clock reference (SCR) is a code meaning a sort of theabsolute time. Based on SCR as the reference, the picture output starttime (presentation time stamp or PTS), as later explained, is set.

The SCR is represented by SCR(i)=C+i*1200, where i is an index number ofa sector in a video data stream and is equal to 0 in the leading frontmargin portion, C is a constant always equal to 0 and 1200 is a valueobtained on dividing a system clock of 90 kHz with 75 Hz(90000/75=1200).

The pack header is provided in each sector V of the video data.

Such pack header is provided in each sector constituted by the pack. Inthe case of the sector V in which the sector records video data, a2312-byte packet following the pack header is configured as shown forexample in FIG. 5B.

That is, the pack header is followed by a 18-byte packet header, theleading three bytes of which constitute a packet start code. The packetstart code is followed by a 1-byte ID, a 2-byte packet length, a 2-bytesystem target decoder (STD), a 5-byte PTS and a 5-byte decoding timestamp (DTS). The picture output start time point (PTS) is set forsynchronizing the video data with audio data. The decoding time stamp(DTS) specifies the decoding start time point. 2294 bytes following thepacket header represent a video packet in which actual video data isrecorded. That is, a video data stream constituted by theabove-mentioned I-, P- and B-pictures is recorded in the video packet.

In a domain having the video sectors V arrayed on end, the video packetin the first video sector V is comprised of 2294 bytes, as explainedpreviously. However, in the succeeding video sectors V, the STD in eachpacket header may be omitted, so that the video packet may be extendedto 2296 bytes.

If the sector is the sector A for recording audio data, the 2312-bytepacket following the pack header is configured as shown for example inFIG. 5C.

That is, the packet header is provided in continuation to the packheader, as in the case of the video sector V. The packet header isconstituted by a 3-byte packet start code, a 1-byte ID, a 2-byte packetlength, a 2-byte STD and a 5-byte PTS, totalling at 13 bytes.

2297 bytes are allocated to an audio packet in which audio data encodedfor compression is recorded. At the trailing end of the audio packet isappended a 20-byte vacant area to constitute a 2324-byte pack or sector.

With the above construction of the sector, the time information itemsfor synchronization are SCR, DTS and PTS. That is, the video sectors Vand the audio sectors A are chronologically arrayed in a track, as shownin FIG. 4, so that the video data and the audio data need to besynchronized with each other. The SCR, DTS and the PTS are used for thissynchronization.

That is, the decoding start time in the video packet or the audio packetis specified by the DTS in each sector, using the SCR as referenceclocks. The outputting time (picture display or speech output) isspecified by the PTS.

Thus the video data of the video sector V and the audio data of theaudio sector A may be synchronized with each other by these timeinformation items.

4. Arrangement on Disc

With the CD-Da, as shown for example in FIG. 6A, a lead-in area isprovided on the inner most periphery of an optical disc for recordingTOC data. The TOC data may be exemplified by the start positions of thetracks (programs), number of tracks, play time or the like.

The lead-in area is followed by tracks #1 to #n for recording audiodata. On the outer most peripheral position is provided a lead-out area.In each track, audio data quantized with the sampling frequency of 44.1kHz and 16 quantization bits are recorded along with the sub-code data.

In the video CD, similarly to the CD-DA, a lead-in area is provided onthe inner most periphery of the optical disc for recording TOC datatherein. The video data is recorded in the tracks #1 to #n nextfollowing the lead-in area. A lead-out area is provided on the outermost peripheral region.

However, with the video CD, the track #1 is used as a video CD datatrack, without being used for recording video or audio data. The actualvideo and audio data are recorded on the tracks #2 to #n. That is, thetracks #2 to #n are configured by the video sectors V and the audiosectors A as shown in FIG. 5.

In the case of the video CD, it is possible to provide tracks in whichonly audio data is recorded, in which case audio data quantized with thesampling frequency of 44.1 kHz and 16 quantization bits, as in the caseof the CD-DA, is recorded.

In both the CD-DA and the video CD, the maximum number of tracks(programs) is 99, so that the maximum of 99 airs and a maximum of 98sequences may be recorded in the case of the CD-DA and the video CD,respectively. The sequence means a partition comprised of a series ofconsecutive moving pictures. If pictures for karaoke are recorded, thesequence is an air (1 track), whereas, with a motion picture, thesequence is usually an optical disc.

In a video CD data track, employing the track #1, the primary volumedescriptor (PVD), a karaoke basic information area, a video CDinformation area, a segment play item area and other file areas, such asCD-I application programs, are provided, as shown at a lower portion ofFIG. 6B. These areas will be explained in detail subsequently.

5. TOC and Sub-code

The TOC and the sub-codes, recorded in the lead-in areas of the video CDand the CD-DA, will be explained subsequently.

The minimum data unit recorded on the video CD and the CD-DA is oneframe. 98 frames make up one block.

588 bits make up on frame, as shown in FIG. 7. The leading 24 bits makeup synchronization data the next following 14 bits make up a sub-codedata area. Data and parity are arrayed next to the sub-code area.

98 of the above frames make up one block. The sub-code data, taken outfrom these 98 frames, constitute one-block sub-code data, as shown forexample in FIG. 8A.

The sub-code data of the first and second frames (frame 98+1 and frame98+2) of the block constitute a synchronization pattern. The sub-codedata of the third frame up to the 98th frame (frame 98n+3 to frame98n+98) constitute data of a P-, Q-, R-, S-, T-, U-, V- and W-channels,each made up of 96 bits.

Of these channels data, the P-channel data and the Q-channel data areused for management for e.g., accessing. The P-channel data representonly the pause portion between tracks, with the Q-channel data takingcharge of finer control.

Specifically, 96-bit Q-channel data (bits Q1 to Q96) are configured asshown for example in FIG. 8B.

That is, the four bits of Q1 to Q4 are used as control data foridentifying the number of audio channels, emphasis and identification ofthe CD-ROM.

For example, the 4-bit control data are defined as follows:

    ______________________________________                                        "0***"         . . . 2-channel audio                                          "1***"         . . . 4-channel audio                                          "*0**"         . . . CD-DA                                                    "*1**"         . . . CD-ROM                                                   "**0*"         . . . digital copying not permitted                            "**1*"         . . . digital copying permitted                                "***0"         . . . no pre-emphasis                                          "***1"         . . . pre-emphasis                                             ______________________________________                                    

It is noted that "****" denotes a binary number in which * may be any of0 or 1.

The four bits of bits Q5 to Q8 represent addresses used as control bitsfor the sub-Q data.

The 4bit address 4 of the bits being "0001" or "0100" means that thesub-Q data of the next following bits Q9 to Q80 is the audio Q-data orthe video Q-data, respectively.

72 bits of bits Q9 to Q80 represent sub-Q data, with the remaining bitsQ81 to Q96 being the cyclic redundancy code (CRC).

In the lead-in are, the sub-Q data recorded therein represents the TOCinformation. That is, the 72-bit sub-Q data, made up of bits Q9 to Q80in the Q-channel data recorded in the lead-in area represents theinformation such as the track number, as shown for example in FIG. 9A.The sub-Q data is made up each of 8 bits.

That is, the track number is recorded first in the lead-in area. In thelead-in area, the track number is fixed at "00" "**" means the binarycoded decimal number).

Next to the track number, there is recorded the point (POINT), followedby minutes (MIN), seconds (SEC) and the frame number (FRAME) specifyingthe elapsed tome in the track.

Then, PMIN, PSEC and PFRAME are recorded. The meaning of the PMIN, PSECand PFRAME is determined by the POINT value.

Specifically, if the POINT value is `01` to `99`, such value specifiesthe track number, and PMIN, PSEC and PFRAME are the minutes, seconds andframe numbers specifying the absolute time address of the start point ofthe track having such track number.

If the POINT value is `A0`, PMIN means the track number of the firsttrack. Distinction between CD-DA, CD-I and CD-ROM (XA designspecification) is made depending upon the PSEC value.

If the POINT value is `A1`, PMIN denotes the track number of the lasttrack.

If the POINT value is `A2`, PMIN, PSEC and PFRAME denote the startingpoint of the lead-out area in terms of the absolute time address.

In the case of an optical disc having e.g., six tracks (programs)recorded thereon, data recorded as shown for example in FIG. 10 arerecorded in the TOC made up of the sub-Q data.

Specifically, the track number TNO is all `00`.

The block NO represents the number of the one-unit sub-Q data read as98-frame block data, as explained previously.

The TOC data of the same contents are recorded over three blocks of theTOC data. If the POINT value is `01` to `06`, PMIN, PSEC and PFRAMEdenote the start point of each of the tracks #1 to #6.

If the POINT value is `A0`, PMIN denotes `01` as the first track number.PSEC is a value used for identifying the optical disc type, as explainedpreviously. If the optical disc is the CD-ROM (XA designspecifications), PEC=`20` as shown. If the optical disc is the CD-DA orCD-I, PEC=`20` or `10`, as shown, respectively.

It is noted that PIN for the POINT value `A1` is the track number of thelast track, while PMIN, PSEC and PFRAME for the POINT value `A2` denotea start point of the lead-out area.

For the blocks n+27 ff., the contents of the blocks n to n+26 areiteratively recorded.

In the tracks #1 to #n and in the lead-out area, the sub-Q data recordedtherein are configured as shown for example in FIG. 9B.

First, the track number is recorded. That is, for the tracks #1 to #n,the track numbers assume any of the values of `01` to `99`. In thelead-out area, the track number is `AA`.

Next to the track number, the information capable of further dividingeach track is recorded as the index.

As the elapsed time in the track, minutes (MIN), seconds (SEC) and theframe numbers (FRAME) are recorded. Further, as AMIN, ASEC and AFRAME,the absolute time address is recorded as the minute (AMIN), second(ASEC) and he frame number (AFRAME), respectively.

6. Directory Construction

FIG. 11 shows the directory structure of the video CD.

The video CD directory, shown in FIG. 6B, is comprised of the video CDdirectory, MPEG audio/video, CD-DA, segment, CD-I, karaoke and EXT, asshown in FIG. 11.

The video CD directory is recorded in the video CD information area inthe track #1 shown in FIG. 6B, and is comprised of a disc informationentry table, a list ID offset table and a play sequence descriptor, eachof which will be explained subsequently.

The MPEG audio/video represents the audio/video sequence data. With thevideo CD capable of recording up to 99 tracks at the maximum, thesequence data is comprised of up to 98 tracks #2 to #99 at the maximum.

The segment is comprised of up to 1980 segment play items #1 to #1980,these being recorded in a segment play item area in the track #1.

Further, the CD-I application program in the track #1 has its directoryfile built as the CD-I into the directory structure. On the other hand,if the karaoke basic information area is to be in use, its directoryfile is built as the karaoke into the directory structure.

If a track having only audio data recorded therein is provided, itsdirectory file is built as the CD-DA in a directory structure, whereas,if PSD₁₃ X.VCD and LOT₁₃ X.VCD are used, the directory files thereof arebuilt as EXT in the directory structure.

7. Video CD Data Track

In the video CD, the track #1 is used as the video CD data track, asmentioned previously.

In the track #1 region, there are recorded the primary volume descriptor(PVD), a karaoke basic information area, a video CD information area, asegment play item area and the like files, such as CD-I applicationprograms, as explained by referring to FIG. 6.

The PVD is arrayed beginning from the position of the absolute timeaddress 00:02:16 (minute: second: frame number) on the disc, as shown inFIG. 6B.

On the other hand, the karaoke basic information area is arrayedbeginning at the position of the absolute time address 00: 03: 00.

The video CD information area is arrayed beginning at the position ofthe absolute time address 00: 04: 00.

The segment play item area and the CD-I application program are arrayedbeginning from the position represented within the video CD informationarea and from the position represented within the CD-I applicationprogram, respectively.

a. Primary Volume Descriptor (PVD)

FIG. 12 shows the structure of the primary volume descriptor (PVD)arrayed beginning from the position of the absolute time address 00: 02:16.

First, as the volume structure standard ID, the CD001h data, where hstands for the hexadecimal number, is recorded. The system identifier,volume identifier, number of album volumes and the album set sequencenumbers are then recorded. Each album is made up of a single opticaldisc or plural optical discs. The number of album volumes represents thenumber of optical discs in one such album. The album set sequence numberrepresents the album disc number.

Next to the album set sequence number, a logical block size, path table,pass table address and the route directory record are recorded.

As the album identifier, the disc tile, publisher and the name of theauthor are recorded.

Then, as he application identifier, the application name of the CD-I isrecorded.

Next to the application identifier, the copyright file number, summaryfile number, table-of-contents file number, date of preparation, date ofcorrection, due date, effective date, file structure version number andthe XA label code are recorded.

b. Video CD Information

The video CD information is recorded beginning from the position of theabsolute time address 00: 04: 00 on the disc, as mentioned previously.

The video CD information is comprised of a disc information entry table,a list ID offset table and a play sequence descriptor (PSD), as shownfor example in FIG. 13. These are of the file structure in the video CDdirectory, as shown and explained in connection with FIG. 11.

The disc information is arrayed beginning from the absolute time address00: 04: 00 representing the leading position of the video CDinformation. The entry table is arrayed beginning from the absolute timeaddress 00: 04: 01. The list ID offset table is arrayed beginning fromthe absolute time address 00: 04: 02 and terminating at the absolutetime address 00: 04: 33. The play sequence descriptor (PSD) is arrayedbeginning from the absolute time address 00: 04: 34 and is present up tothe absolute time address 00: 07: 64 at the maximum.

b1. Disc Information

The disc information arrayed beginning at the absolute time address 00:04: 00 is explained. FIG. 14 shows the structure of the discinformation.

The system identifier of the video CD is recorded at the first to eighthbytes.

The version number is recorded at two bits, i.e., the ninth and tenthbytes. This version number is 0200h for the version 2.0.

The album descriptor proper to each optical disc is recorded at the 16bytes of from 1st to 26th bytes.

The number of volumes in the album is recorded at two bytes, that is atthe 27th and 28th bytes. The album set sequence number is recorded inthe next following two bytes. The number of volumes in the album is thenumber of the optical discs used for recording the sole album, asexplained previously. The album sequence number identifies theoptical(disc number.

The size map of the moving picture track is recorded at 13 bytes of the31st to 43rd bytes. The size map is the data used for judging whetherdata recorded in the tracks #2 to #99 is the signal of the NTSC systemor that of the PAL system. Specifically, the LSB of the first one of 13bytes specifies the track #2. The bits from this LSB up to the bit b1 ofthe last byte each record data up to the track #99. The bits 0 and 1corresponding to the tracks denote the NTSC system and the PAL system,respectively.

A status flag is recorded at the 44th byte. Among bits b₀ (LSB) up to b₇(MSB) of this one byte, the bit b₀ is a flag of the karaoke basicinformation flag. Specifically, the bit b₀ equal to 0 indicates theabsence of the karaoke basic information. On the other hand, the bit b₀equal to 1 indicates the presence of the recorded karaoke basicinformation. At the four bytes of the 45th to 48th bytes, the byte sizeof the play sequence descriptor (PSD) is recorded. The PSD is recordedbeginning from the absolute time address 00: 04: 34 and terminating atthe absolute time address 00: 07: 64 at the maximum, with the byte sizebeing variable, as shown in FIG. 13. Thus the PSD byte size is recordedhere. The PSD is made up of plural lists, that is a selection list, aplay list and an end list, used for playback control, each list beingrecorded as the PSD, as will be explained subsequently. If there is noPSD, that is in case of an optical disc not having the playback controlfunction, these four bytes are all set to 00h.

The first segment address is recorded in three bytes of the 49th to 51stbytes. It has been stated in connection with FIG. 6B that the startpoint of the segment play item area is recorded in the video CDinformation area. This area corresponds to these three bytes. Althoughthe segment play items are not described in detail, up to the maximum of1980 segment play items can be recorded in the segment play item areashown in FIG. 6B. The respective segment play items are comprised ofvideo data or audio data employed for playback control or the like.

An offset multiplier is recorded at the 52nd byte. The multiplier isused for calculating the address of each list in the PSD and is set toe.g., 8.

The number of the list IDs is recorded at two bytes, that is at the 53rdand 54th bytes. The number of the list IDs specifies the number ofeffective lost IDs recorded in the ID offset table which will beexplained subsequently.

The number of segment play items recorded in the segment play item areais recorded at two bytes, that is at the 55th and 56th bytes.

The segment play item contents table is recorded at 1980 bytes of the57th to 2036th bytes. The segment play item contents table specifies theattributes of the segment play items recorded in the segment play itemarea. That is, up to the maximum number of 1980 segment play items arerecorded as the segment play items #1 to #1980. The segment play itemcontents table is comprised of 1-byte attribute data associated with thesegment play items #1 to #1980, as shown for example in FIG. 15.

Specifically, the attribute data is defined for each of bits b₀ to bit₇of one byte, as shown below. The bits b₆ and bit b₇ are not defined.

bits b₁ and b₀

    ______________________________________                                        "00"      . . . there is no MPGb audio data                                   "01"      . . . monaural audio data                                           "10"      . . . stereo audio data                                             "11"      . . . dual channel audio data bits b.sub.4 to b.sub.2               bits b.sub.4 to b.sub.2                                                       "000"     . . . there is no MPEG video data                                   "001"     . . . still picture data of the standard level                                of the NTSC size                                                    "010"     . . . still picture data of the picture data of the                           high definition level                                               "011"     . . . moving picture data of the NTSc size                          "100"     . . . not in use                                                    "101"     . . . still picture data of the standard level of the                         PAL size                                                            "110"     . . . still picture data of the standard level and                            high definition level of the of the PAL size                        "111"     . . . moving picture data of the PAL size                           bit b.sub.5                                                                   "0"       . . . sole item or leading one of continuous items                  "1"       . . . second and following items of continuous                      ______________________________________                                                  items                                                           

The bytes beginning from the segment play item contents table andterminating up to the 2037th to 2048th bytes of the disc information arenot defined.

b2. Entry Table

In the video CD information area, the entry table is arranged so as tobegin at the absolute time address 00: 04: 01, as shown in FIG. 13.

In the entry table, a pre-set point within the audio/video sequence maybe entered as a starting point.

Thus, in the present entry table, the ID identifying an entry file,version number or the number of entries are recorded and up to a maximumof 500 entries are recorded as the actual entry points. That is, theentries #0 to #499 may be set.

Each entry is made up of 4 bytes, of which one byte specifies the tracknumber and the remaining three bytes specify the sector address, that isASEC, AMIN and AFRAME.

b3. List ID Offset Table

In the sectors of the video CD information area beginning from theabsolute time address 00: 04: 02 and ending at 00: 04: 33, a list IDoffset table is arranged.

The play list or the selection list, recorded in the PSD as laterdescribed, is provided with the intrinsic list ID. In the list ID offsettable are shown offset quantities specifying the positions of therespective lists. If the user designates the list desired to bereproduced, the reproducing device reproducing the video CD refers tothe list ID offset table for grasping the position of the designatedlist in the PSD for allowing the contents of the list to be executed.

The list ID offset table is made up of 32 sectors at the maximum, asshown for example in FIG. 16. Each offset quantity is specified by 2bytes, so that a 24k-number of offsets may be represented.

The PSD area, later described, has the absolute time address of from 00:04: 34 up to the maximum of 00: 07: 64, so tat it represents an area of3 seconds 31 frames at the maximum. This is equivalent to 256 sectors or512 kbytes.

The 64k-number of the offsets, represented by the list ID offset table,is multiplied with 8 to give 512 kbytes. This multiplier value of 8 isthe offset multiplier of the 52nd byte of the disc information shown inFIG. 14.

That is, one offset is equivalent to 8 bytes, so that, by multiplyingthe offset value with the offset multiplier 8, the pre-set position inthe PSD area may be represented as the byte position from the leadingposition of the PSD (offset 0000h position).

In the list ID offset table, the start-up offset is first recorded, asshown in FIG. 16. This start-up offset is fixed at a value of 0000h.

FIG. 16, showing the case with the number of ID of n, gives offsetvalues for the list ID1 to list IDn.

Meanwhile, the offset value of the 1st ID1, which is necessarily arrayedat the leading end of the PSD, is fixed at a value of 0000h.

The list ID, which is not in use, is fixed at a value of FFFFh.

b4. Play Sequence Descriptor (PSD)

The PSD is provided beginning from the absolute time address 00: 04: 34.

In this PSD are recorded the play list, selection list and the end list.In these lists, used for playback control as later explained, there arerecorded the playback contents and data specifying the layer branchingpoints.

The play list is such a list not containing data for branching to alower layer, referred to hereinafter as the selection menu, and isemployed for designating a series of contents to be reproduced.

On the other hand, the selection list is such a list containing aselection menu for branching to a lower layer.

Meanwhile, the list (play list or selection list) to be reproduced firstis the list ID1 and is recorded at the leading position of the PSD(offset 0000h position).

Play List

The play list designating a series of contents to be reproduced isconfigured as shown for example in FIG. 17.

That is, a 1-byte play list header is provided for specifying that thelist is the play list.

Next to the play list header, there is recorded, as the number of items,the number of play items recorded in the play list. The play item is thedata specifying the contents to be reproduced. That is, data specifyingthe play items are recorded in the play list as being the play item #1number to play item #1 number.

Next to the number of item data, a 2-byte list ID, proper to each list,is recorded.

Next to the list ID, the previous list offset, next list offset and thereturn list offset, each comprised of 2 bytes, are recorded.

The previous list offset specifies the position (offset) of the list towhich the operation transfers after the previous operation has beenperformed. If the list is to be layered, and the position of a list ofthe next upper order is specified by the previous list offset, the usermay perform the previous operation for restoring the operating statewhich is based upon the previous list.

If the previous list offset is FFFFh, the previous operation isinhibited.

The next list offset specifies the position of the list to which theoperation is to transfer in continuation after the reproducing operationdesignated by the play list comes to a close or when the next operationhas been performed. If the next list offset is FFFFh, the next operationis inhibited.

The return list offset specifies the position of the list to which theoperation is to transfer when the return operation has been performed.For example, if the list is to be layered, and the upper most order listposition is specified by the return list offset, the user may performthe return operation for restoring the operating state at a time to anoperating state which is based upon the list of the upper most order.

Next to the return list offset, the 2-byte playing time, a 1-byte playitem weight time, and a 1-byte auto-pause weight time are recorded.

The playing time specifies the number of sectors of the reproducingoperations which is based upon this play list.

The play item weight time specifies the stand-by time until end ofreproduction of respective play items. Specifically, the stand-by timeof 0 to 2000 seconds is represented by 00h to FEh. The number FFhspecifies waiting for the user's operation.

The auto-pause weight time denotes the standby time in the course of theauto-pause operation.

Finally, the numbers of the items #1 to #N to be reproduced are recordedby respective two bytes.

This play item number (PIN) is defined as shown for example in FIG. 18.

If PIN=0 or 1, such play item number specifies that nothing isreproduced.

If PIN=2 to 99, such play item number specifies the track number. IfPIN=5, for example, the play item is that reproducing the track #5.

If PIN=100 to 599, subtraction of 100 from the PIN (PIN-100) gives theentry in the entry table. The entry table ia able to specify up to themaximum number of 500 of the entry points, by setting the entries #0 to#499, such that the value of (PIN-100) specifies one of the entrynumbers of from #1 to #500.

If PIN=1000 to 2979, subtraction of 999 from the PIN gives the number ofthe segment play item. In the segment play item area, up to a maximumnumber of 1980 of segment play items may be recorded, by setting thesegment play items #1 to #1980, such that subtraction of 999 from thePIN (PIN-999) gives one of the segment play items of from #1 to #1980.

PIN=600 to 999 and PIN=2980 to 65535 remain undefined.

If three play items are recorded in the play list, and the play item #1number, play item #2 number and the play item #3 number are 4, 1001 and102, respectively, the reproducing operation performed by the play listis such a reproducing operation in which the track #4 is reproducedfirst, the segment play item #2 is then reproduced and finally thereproduction from the entry point which is based upon the entry #3 iscarried out.

Selection List

The selection list is such a list for displaying a selection menu on adisplay screen for allowing the user to select the operation to whichthe operation is to transfer. The selection list is configured as shownfor example in FIG. 19.

That is, a 1-byte selection list header is provided thus indicating thatthe list is the selection list.

Next to the selection list header, a 1-byte number of alternatives inthe selection list is recorded with the interposition of a 1 byte whichis not in use. The number of alternatives is 99 at the maximum.

The first number of the alternative is then recorded. The first numberof the alternative is usually 1. However, if there are a large number ofalternatives to be selected, and hence plural selection lists are used,such number in each of the second and the following selection lists isthe first number of the alternative in such list.

Next to the list ID, a previous list offset, a next list offset, and areturn list offset, each consisting of two bytes, are recorded, as inthe case of the play list.

The previous list offset specifies the position of the list (offset) towhich the operation is to transfer in case the previous operation hasbeen performed. If the previous list offset is FFFFh, the previousoperation is inhibited.

The next list offset indicates the position of the selection list towhich the operation is transfer in continuation when the next operationhas been performed. If there is no list to which the operation is totransfer in continuation, the offset is set to FFFFh.

The return list offset denotes the position of the list to which theoperation is to transfer in case the return operation has beenperformed.

If setting is made so that one selection is done in plural selectionlists, these may be exploited effectively. For example, if 12alternatives are set, and four alternative are set in each of the threeselection lists, the respective selection lists are interconnected inthe forward and backward directions by the previous list offset and thenext list offset in order to permit the user to search the desiredalternative by the previous or next operation.

Next to the return list offset, a two-byte default list offset isrecorded. This indicates the position of the list to which the operationis to transfer when the user performs an actual operation without makingselections.

On the other hand, a two-byte timeout list offset is recorded. Thisindicates the position of the list to which the operation is to transferwhen a pre-set time has elapsed without the user performing anyinputting operation on the reproduced and displayed selection menu. Ifthe timeout list offset is FFFFh, a particular alternative is selectedat random from among the alternatives shown in the selection menu at atime point when a pre-set time has elapsed without input. The operationtransfers to this selected alternative.

Next to the timeout list offset is recorded a 1-byte wait time untiltimeout. If the recorded wait time has elapsed without any input by theuser, the operation is to transfer to the above-mentioned timeout listoffset.

The value recorded in the wait time until timeout is defined as shownfor example in FIG. 20.

If the recorded timeout value is 00h(0), the standby time is set to bezero.

If the recorded wait time value is any one of 01h(1) to 3Ch(60), thevalue directly denotes seconds. For example, if the wait time value is30, the standby time is 30 seconds.

If the recorded wait time value is 3Dh(61) or 3Eh(62), the standby timeis 70 seconds and 80 seconds, respectively. That is, for the wait timevalue of 61 or larger, the standby time is defined by (n-60)×10+60seconds. If the wait time value is FEh, the standby time is the maximumstandby time. That is, since FEh is 254, the standby time is 2000(=(254-60)×10+60) seconds.

If the wait time value is FFh, the operating state based upon theselection list is to keep waiting until the next input.

Next to the wait time until timeout, a loop count and the jump timing,each being 1 byte, are recorded. The loop count and the jump timingindicate the number of times of repetition of the play item in the listand the timing to transfer to the next 1st after the selecting operationhas been performed.

Next to the loop count and the jump count, a 2-byte play item number(PIN) is recorded. The PIN denotes, by the definition shown in FIG. 18,the play item to be reproduced in the state of execution of theselection list. It is usually the still picture data for displaying themenu on the picture that is reproduced in the selection list. Thus thevideo data for menu is recorded as the segment play item. In many cases,a specified segment play item is designated in each selection list.

If, for example, the data for the menu screen associated with theselection list is recorded as the segment play item #4, the PIN is 1003.

This, one PIN is provided in the selection list.

Finally, for specifying the operation to be executed by selection withinthe alternatives, there are recorded selection #BSN offset to selection#(BSN+NOS-1) offset, each comprised of two bytes. BSN and NOS denote thefirst number of an alternative recorded in the fourth byte of theselection list and the number of alternatives recorded in the third byteof the selection list. Thus, in the selection list having alternatives 1to 4, the selection #1 offset to selection #4 offset are recorded.

These selection offsets indicate the position of the list (selectionlist or the play list) to which the operation is to transfer when thealternative is selected.

If, for example, the user selects the alternative 2 on the menu display,the operation is designated to transfer to the list indicated by theselection #2 offset.

End List

The end list specifies the terminal end of the application. The end listhas eight bytes, of which one is an end list header and the remainingseven bytes are all set to 00h.

c. Segment Play Item

In the video CD data track, there is provided a segment play item area,as shown in FIG. 6. The start point of the segment play item isindicated by three bytes, that is the 49th to 51st bytes, of the discinformation, as indicated in FIG. 14.

Up to a maximum number of 1980 of the segment play items can be recordedin the segment play item area.

The respective segment play items can be freely generated by stillpicture data, moving picture data, audio data or the like.

Each segment is made up of 150 sectors. Each segment play item may bedata reproduced as sole items or plural continuously reproduced items.

Each segment play item has its data attributes represented by segmentplay item contents table of the 57th to 2036th bytes in the discinformation table, as explained in connection with FIG. 15.

Using the segment play item, menu screens for the selection list may beprovided, as explained previously.

II. Playback Control (PBC)

1. List Structure

By pre-recording the play list and the selection list on the video CD asexplained previously, it becomes possible with a video CD reproducingdevice to implement playback control. That is, the video D functions asa simple interactive software which represents the combination of themoving pictures, still pictures and the speech.

Specifically, it is possible with the video CD to record several stillpicture data of a menu screen in the segment play item area as segmentplay items and to enable several branching reproduction and to reproducethe play items selected by branching in accordance with the play list.In other words, it is possible with the video CD to form a descriptionfile layered by the selection list and the play list and to transfer toa lower order layer responsive to user selection in order to carry outthe desired reproducing operation.

As the basic list structure, the selection list is arrayed at an uppermost order position and several play lists are provided as alternativesof the selection list. For example, specified play lists are designatedas the selection #1 offset to selection #3 offset for the selectionlist. The reproducing device displays the menu on the screen based uponthe selection list in order to permit the user to select the menu.

If, for example, the user selects the selection #3, the reproducingdevice transfers to the play list specified by the selection #3 offset,and reproduces data specified as the play item #1 number to play item #Nnumber of the play list. For example, if the track #5 is designated as aplay item #1 number in the play list to which the operation hastransferred, the reproducing device executes reproduction of the tracknumber #5.

2. Illustrative Example

An illustrative example of the playback control operation by thereproducing device is explained by referring to FIGS. 21 and 22. In thepresent illustrative example, a video CD is a software of a lesson inEnglish conversation.

It is assumed that the selection list and the play list are recorded asthe play sequence descriptor (PSD) from the position of the absolutetime address in the video CD information area, as shown for example inFIG. 21. That is, selection list Si and S2 and the play lists P1 to P5are recorded.

For each list, a list ID is appended, as shown in FIG. 22. That is, asthe list ID, 0001h, 0002h, 0005h, 0006h, 0007h, 0003h and 0004h arerecorded for the selection list S1, selection list S2, play list P1,play list P2, play list P3, play list P4 and play list P5, respectively.

The reproducing device entering the playback control operationreproduces and executes the selection list S1 whose list ID is 0001h.

Specifically,the reproducing device reproduces play item numbers (PIN)recorded in the selection list S1 based upon the selection list S1. Inthe PIN is recorded a value 1000. This value 1000 is a value indicatingthe segment play item #1, as indicated in FIG. 18. The reproducingdevice reproduces the segment play item #1 recorded in the segment playitem area.

In the segment play item #1 is recorded still picture data forrepresenting the menu picture PB1 for selecting the course of theEnglish lesson, as shown in FIG. 22. The reproducing device displays themenu picture PB1.

In the selection list S1 are recorded the selection #1 offset to theselection #3 offset associated with the three alternatives. Thereproducing device displays a menu comprised of three alternatives basedupon the segment play item #1. Meanwhile, Se1#N in the drawings denotesthe selection #N offset.

The user enters a desired alternative number for the menu picture PB1.If, for example, the user inputs the alternative number 1, thereproducing device reproduces the list indicated in the selection #1offset. The selection #1 offset is 0004h. The reproducing devicemultiplies the value with the multiplier 8 to give a value 0020h whichis an offset representing the position of the selection list in the PSDin terms of the number of bytes (offset bytes).

In the PIN in the selection list S2, a value 1001 is shown. This PINdenotes the segment play item #2. Thus the reproducing device reproducesthe segment play item #2.

In the segment play item #2 is recorded still picture data fordisplaying the menu picture PB6 for selecting lesson courses 1 to 3 inthe senior course of the lessons in English. The reproducing devicedisplays the menu picture PB6.

If the user inputs the alternative number 1 for selecting the lesson 1of the senior course, the reproducing device reproduces the listindicated in the selection #1 offset in the selection list S2. Theselection #1 offset value is 0008h. The reproducing device multipliesthe value with the offset multiplier 8 to give 0040h. The reproducingdevice then reproduces 0040h, that is the play list P1.

In the play list P1, "2" is recorded as PIN #1. That is, the track #2 isdesignated. On the other hand, "3" is recorded as the PIN #2, so thatthe track #3 is designated. Thus, in executing the play list P1, thereproducing device reproduces the track #2 for displaying the movingpicture PB7 while outputting the speech associated with the movingpicture PB7. The moving picture PB7 and the speech, reproduced from thetrack #2, are the moving picture and speech for the senior course lesson1.

When the reproduction of the track #2 comes to a close, the reproducingdevice reproduces the track #3 for displaying the moving picture PB8 andoutputting the speech.

If, as the menu picture PB6 is being displayed based upon the selectionlist S2, the user enters the alternative number 2, the reproducingdevice reproduces the list specified by the selection #2 offset in theselection list S2, that is the play list P2.

In the play list P2 is recorded "1002" as PIN#1. That is, the segmentplay item #3 is designated. Thus the reproducing device reproduces thesegment play item #3, in executing the play list P2, and displays e.g.the still picture PB9, while outputting the speech associated with thestill picture PB9. The still picture PB9 and the speech are the stillpicture and the speech in the slide show in e.g., the senior courselesson 2.

If, when the menu picture PB6 is displayed, based upon the selectionlist S2, the user inputs the alternative number 3, the reproducingdevice reproduces the list indicated on the selection #3 offset in theselection list S2, that is the play list P3.

In the play list P3, there is recorded "8" as PIN#1, that is, the track#8 is designated. If this track #8 is a track only of e.g., digitalaudio data, the reproducing device reproduces the track #8 for thesenior course lesson 3 and outputs only the speech (PB10).

If, when the menu picture PB1 based upon the first selection list S1 isdisplayed, the user inputs the alternative number 2 for the seniorcourse, the reproducing device reproduces the list indicated on theselection #2 offset in the selection list S2, that is the play list P4.

In the play list P4, there is recorded "4" as PIN#1, that is the track#4 is designated, while there is recorded "5" as PIN#2, that is thetrack #3 is designated. Thus the reproducing device first reproduces thetrack #4, in executing the play list P4, for displaying the movingpicture PB2 and outputting the speech, and then proceeds to reproducingthe track #5 for displaying the moving picture PB3 and outputting thespeech. These moving pictures and the speech represent the movingpicture and speech of the senior course.

If, when the menu picture PB1 based upon the first selection list S1 isdisplayed, the user inputs the alternative number 3 for the juniorcourse, the reproducing device reproduces the list indicated on theselection #3 offset in the selection list S1, that is the play list P5.

In the play list P5, there is recorded "6" as PIN #1, that is the track#6 is designated, while there is recorded "7" as PIN #2, that is thetrack #7 is designated. Thus the reproducing device first reproduces thetrack #6, in executing the play list P5, for displaying the movingpicture PB4 and outputting the speech. The reproducing device thenproceeds to reproducing the track #7 for displaying the moving picturePB5 and outputting the speech. These moving pictures and the speechrepresent the moving picture and speech of the junior course.

The previous list offset, next list offset and the return list offsetmay be recorded in the play list and the selection list, as explainedpreviously. A default list offset and a timeout list offset may also berecorded in the selection list. Based on these offsets, the reproducingdevice is able to advance or recede the list responsive to the user'soperation.

If 0004h, for example, is recorded as the previous list offset in theplay list P1, and the user executes a previous operation duringexecution of the play list P1, the reproducing device returns to theselection list S2 whose offset is 0004h, that is the offset byte 0020h.

Thus a video CD may be designed as a simplified interactive typesoftware by playback control. By this function, the video CD may be usedin a wide range of applications for education, game or electronicpublication besides music and motion picture.

III. Illustrative Construction of Reproducing Apparatus

1. Appearance

A video CD player for reproducing the video CD, according to the presentinvention, is now explained.

This video CD player is provided with a so-called changer forselectively reproducing five video Cds or CD-DAs.

This video CD player has a disc loader 2 provided on a front panel of amain body 1 and designed for drawing out a disc tray 30 on its frontside, as shown for example in FIG. 23. The disc tray 30 has five loadingpositions 30₁ to 30₅, as shown for example in FIG. 24. In these fiveloading positions 30₁ to 30₅, optical discs may be placed horizontallyand rotated like roulette for selecting the optical disc to bereproduced.

A display section 3 is provided on the front panel of the main body 1.The display section 3 is formed e.g., by a liquid crystal panel andindicates the operating state and the mode of the video CD play, thenumber or the play time of the selected optical disc and so forth.

On the front panel are mounted a variety of keys actuated by the user.Specifically, a power on/off key 4, a playback key 5, a pause key 6, astop key 7 and an ejection key 8 are provided. The playback key 5 isalso used as a selection key for performing the above-mentioned playbackcontrol operation.

A disc selection key 9 is provided on the front panel. The discselection key 9 has five keys D1 to D5 associated with the loadingpositions 30₁ to 30₅ of the disc tray 30, respectively. If, for example,the key D1 is pressed, the optical disc loaded at the loading position30₁ of the disc tray is loaded on the position of an optical head 34 aslater described for reproducing the optical disc.

On the front panel, a rear locating key 10 and a front locating key 11are provided for automatic music sensor (AMS) operation. The frontlocating key 10 is a locating key in a direction of the decreasing tracknumber, while the rear locating key 11 is a locating key in a directionof the increasing track number. The rear locating key 10 is also used asa previous key for the previous operation during the above-mentionedplayback control operation. The front locating key 11 is also used as anext key for the next operation during the above-mentioned playbackcontrol operation.

A return key 12 is provided on the front panel and is used for a returnoperation during the playback control operation.

A +/- selection key 13 is provided on the front panel so as to be usedfor a selection operation on the menu screen during playback control.That is, the alternative number selection is performed using the +/- key13 on the menu screen and, at a time point when a certain alternativenumber is selected, the selecting operation is performed using theplayback key 5 for completing the menu selection.

On the front panel, there are provided a disc skip key 14, a discexchange key 15, a normal playback mode key 16, a shuffle playback modekey 17, a program playback mode key 18 and a PBC off key 19. The normalplayback mode key 16 to the PBC off key 19 are play mode selection keys.When the video CD having the playback control function is to bereproduced, the normal playback mode key 16 is pressed, whereby thevideo CD player automatically enters the playback control operation. If,during the playback control operation, the PBC off key 19 is pressed,the video CD player transfers from the menu playback operation of thePBC mode to the normal playback operation. That is, the PBC off key 19is a key used for turning off the PBC mode.

A digest key 20 and a digest mode key 21 are provided on the frontpanel. The digest key 20 is used for displaying the digest concerningaccommodated optical discs. The digest mode key 21 enables selection asto whether the digest picture concerning the video CD having theplayback control function is to be a menu picture or an in-trackpicture.

A book mark registration key 22 and a book mark reproducing key 23 areprovided on the front panel. The reproducing point, referred tohereinafter as a book mark point, is registered by the user pressing thebook mark registration key 22 during reproduction. Reproduction mayproceed beginning from the book mark point by pressing the book markreproducing key 23. Five book mark points, for example, may bedesignated and registered for a single optical disc by the book markregistration key 22.

If, after pressing the book mark reproducing key 23, the user selectsone of the registered book mark points, reproduction is started from theselected point. The +/- selection key 13 and the reproducing key 5, forexample, are employed for selecting the registered book mark point.

An infra-red reception unit 24 is provided on the front panel. Theinfra-red reception unit 24 receives a command signal transmitted frome.g., a remote commander, not shown, and transmits the command signal asthe operating information to a system controller 53 as later explained.2. Illustrative Circuit construction Referring to FIG. 24, the vide CDplayer includes a motor 31 for rotationally driving the disc tray 30, adisc position sensor 32 for detecting which of the loading positions 30₁to 30₅ on the disc tray is at the position of an optical head 34, aspindle motor 33 for rotationally driving the optical disc, the opticalhead 34 for reproducing the information, such as video data, from theoptical disc, a thread mechanism 35 for driving the optical head 34along the radius of the disc, an RF amplifier 36 for amplifying playbackRF signals from the optical head 34 and for generating tracking errorsignals or the like, a servo circuit 37 for effecting tracking controlfor the optical head 34 based upon tracking error signals from the RFamplifier 36, a decoding unit (decoder) 38 for demodulating playback RFsignals from the RF amplifier 36, a CD-ROM decoder 39 for decoding theinformation from the decoding unit 38 in accordance with the CD-ROMformat, an MPEG audio decoder 40 for decoding audio data from the CD-ROMdecoder 39, an audio RAM 41 for transiently storing the audio data, anMPEG video decoder 42 for decoding video data from the CD-ROM decoder39, a video RAM 43 for transiently storing the video data, a changeoverswitch for selectively switching between audio data from the decodingunit 38 and that from the MPEG audio decoding unit 40, a D/A converter45 for converting audio data from the changeover switch 44 into analogaudio data, a D/A converter 47 for converting video data from the MPEGvideo decoder 42 into red (R), green (G) and blue (B) video signals, anRGB/NTSC encoder 48 for converting the video signal from the D/Aconverter 47 into composite video signals, a changeover switch 49 forselectively switching between composite video signals from the RGB/NTSCencoder 48 and from a CD-G decoder 52, an OSD processing unit 50 foreffecting superimposing display, the CD-G decoder 52 for convertingstill picture data from the decoder 38 into composite video signals, asystem controller 53 for controlling the above-mentioned respectivecircuits based upon the playback control information from the CD-ROMdecoder 39, a RAM 54 for storing the results of processing by the systemcontroller 53, a back-up power source 55 for supplying the current tothe RAM 54, and an operating unit 56 comprised of the above-mentionedoperating keys 5 to 23.

The disc tray 30, having the five loading positions 30¹ to 30₅, forenabling the loading of the five optical discs, is run into rotation bythe motor 31 so that one of the loading positions is sent to theposition of the optical head 34 by the motor rotation. That is, theoptical disc loaded on the loading position 30 is loaded on the positionof the optical head 34. The disc position sensor 32 detects which of theloading positions 30 is at the position of the optical head 34 and sendsthe results of detection to the system controller 53.

The loaded optical disc is chucked and then run in rotation by thespindle motor 33. The optical disc is illuminated by the optical head 34with the laser light, as the disc is rotated, so that the information isread by the reflected light.

Specifically, the optical head 34 is provided with an optical systemcomprised e.g., of a laser diode, a polarized beam splitter or anobjective lens 34a, and a detector for detecting the reflected light.The objective lens 34a is held by a so-called biaxial mechanism 34b fordisplacement in a direction along the radius of the optical disc and ina direction along the optical axis of the disc. The optical head 34 isalso driven by the thread mechanism along the radius of the disc.

The optical head 34 detects playback RF signals responsive to theinformation, such as audio data, recorded on the optical disc, and sendsthe detected signals to the RF amplifier 36. The RF amplifier 36amplifies playback RF signals and processes detector outputs forgenerating tracking error signals and focusing error signals. Theamplified playback RF signals are sent to the decoding unit 38, whilethe tracking error signals and the focusing error signals are sent tothe servo circuit 37.

The servo circuit 37 generates various servo driving signals, based uponthe tracking error signal and the focusing error signals supplied fromthe RF amplifier 36, track jump commands and access commands sent fromthe system controller 53 and the rotational speed detection informationfor the spindle motor 33 and controls the biaxial mechanism 34b and thethread mechanism 35 by these servo driving signals for effectingfocusing control and tracking control. The servo circuit 37 alsocontrols the spindle motor 33 so that the optical disc will be rotatedat a constant linear velocity.

The decoding unit 38 converts the playback RF signals supplied from theRF amplifier 36 into bi-level signals for reproducing the audio andvideo data, while correcting the data for errors by error correctionprocessing employing EFM (eight-fourteen demodulation) or CIRC (crossinterleaved Reed-Solomon code). If the optical disc being reproducedfalls under the category of the CD-ROM, exemplified by a video CD, thedecoding unit 38 sends the produced audio data and video data to theCD-ROM decoder 39. If the optical disc being reproduced is the CD-DA,the produced audio data is sent to the changeover switch 44, while thevideo data is sent to the CD-G decoder 52. The decoding unit 38 sendsthe reproduced P and Q channel sub-code data to the system controller53.

If the optical disc being reproduced is e.g., a video CD, the CD-ROMdecoder 39 decodes the audio data and the video data supplied from thedecoding unit 38 in accordance with the CD-ROM format. The audio dataand the video data, decoded by the CD-ROM decoder 39, are sent to theMPEG audio decoder 40 and the MPEG video decoder 42, respectively. Ofthe information decoded by the MPEG decoder 39, the disc information ofvarious sorts, such as the information for the above-mentioned playbackcontrol, is sent to the system controller 53 so as to be transientlystored in a RAM 53a of the controller 53.

The MPEG audio decoder 40 decodes audio data supplied from the CD-ROMdecoder 39, at a pre-set timing, using the audio RAM 41, and sends thedecoded audio data to the changeover switch 44.

The changeover switch 44 is such a changeover switch which is changedover responsive to the sorts of the optical disc being reproduced undercontrol by the system controller 53. If the optical disc beingreproduced is the CD-DA, the audio data, decoded by the EFM demodulationand error correction, is obtained by the decoder 38. Thus, during theCD-DA reproduction, the system controller 53 connects the selectionterminal of the changeover switch 44 to a terminal t1. This sends theaudio data from the decoder 38 to the D/A converter 45. The D/A decoder45 converts the audio data into analog audio signals which are outputtedvia an audio output terminal 46 to a downstream side external equipment,such as a monitor unit.

On the other hand, if the optical disc being reproduced is the video CD,the audio data is obtained from the MPEG audio decoder 40. Thus, duringreproduction of the video CD, the system controller 53 causes theselection terminal of the changeover switch 44 to be connected to aterminal t2. This causes audio data from the MPEG audio decoder 40 to besent to the D/A converter 45. The D/A converter 45 converts the audiodata into audio signals which are outputted via an audio output terminal46 to the external equipment.

The MPEG video decoder 42 decodes the video data supplied from theCD-ROM decoder 39, during reproduction of the video CD, using the videoRAM 43, and transmits the resulting RGB video data to the D/A converter47.

The D/A converter 47 converts the video data supplied from the MPEGvideo decoder 42 into analog signals and transmits the resulting RGBvideo signals to the RGB/NTSC encoder 48. The RGB/NTSC encoder 48converts the RGB video signals into composite video signals of the NTSCsystem and sends the resulting signals to the terminal t2 of thechangeover switch 49.

The changeover switch 49 is also such a changeover switch which ischanged over responsive to the sorts of the reproduced optical discunder control by the system controller 53. If the video CD isreproduced, the RGB video data is obtained from the MPEG video decoder42 as the playback data of the optical disc. Thus, during reproductionof the video CD, the system controller 53 causes the selection terminalof the changeover switch 49 to the terminal t2, so that the changeoverswitch 49 allows the composite video signals from the RGB/NTSC encoder48 to be supplied to the OSD processing unit 50. The OSD processing unit50 performs preset superimposing processing on the composite videosignals under instructions by the system controller 53 and sends theprocessed signals via a video output terminal 51 to an externalequipment, such as a monitoring unit.

If the optical disc being reproduced is the CD-DA and especially a CD-G,still picture data (video data of the still picture) are read out fromthe R to W sub-code channels of the optical disc. Thus the CD-G decoder52 decodes still picture data supplied from the decoding unit 38 totransmit the resulting composite video signals of the NTSC system (stillpicture) to the terminal t1 of the changeover switch 49. Duringreproduction of the CD-DA, the system controller 53 causes the selectionterminal of the changeover switch 49 to be connected to the terminal t1.The changeover switch 49 causes the composite video signal from theCD-DA decoder 52 to be supplied via the OSD processing unit 50 and thevideo output terminal 51 to the external equipment.

The RAM 54 has memory data backed up by the backup power source 55. Inthe RAM 54, data which should not be lost on power down, such asregistered data of the book mark points, are stored. An EEP-ROM, forexample, may naturally be employed in place of the RAM 54.

The operating unit 56 is equivalent to the operating keys 5 to 23 shownin FIG. 23 and to the IR reception unit 24 (with the remote commander)and sends a signal responsive to the user's operation to the systemcontroller 53. For reproducing the optical disc, managemental datastored on the optical disc, that is the TOC or the sub-code data, isread out, while the system controller 53 is responsive to themanagemental data supplied form the decoder 38 for displaying theplayback time on the display unit 3.

IV. Random Reproducing Operation during PBC Operation

With the conventional reproducing device, such as the CD player, theprogram of a number corresponding to the random number generated by theinternal random number generator is reproduced when the user presses aoperating bouton commanding random reproduction. However, theconventional reproducing device has such drawbacks that the programreproduction is not automatically performed in the absence of actuationby the user, the reproduced programs are reproduced twice or more, orthe program reproducing sequences tend to be the same for the firstrandom reproduction and the second random reproduction, thus sufferingfrom insipidity in the reproducing sequences. The vide CD player of theinstant embodiment is designed so that, in such random programreproduction, program selection will be made ubiquitously.

The operation is hereinafter explained.

The playback control operation has been explained above by referring toillustrative examples shown in FIGS. 21 and 22. For explanation sake, adirectory of a simple list structure shown in FIG. 25 is now used. Thatis, it is assumed that five alternatives are provided for the selectionlist S1 and five play lists P1 to P5 are designated by the respectivealternatives. FIG. 26 shows this directory taking the representation ofFIG. 22 into account.

It is assumed that the list ID for the selection list S1 is 0001h, andthat FFFFh is entered in the selection list S1 as the timeout listoffset (TL-OF) explained in connection with FIG. 19, thus specifyingthat random alternative selection be made responsive to the timeout. Itis also assumed that the value of the wait time until timeout (W-TO) is30, that is the standby time of 30 seconds is designated. It is alsoassumed that Se1#1 to Se1#5 are provided as selection #BSN offset, suchthat there are five alternatives, and that Se1#1 to Se1#5 designate theplay lists P1 to P5, respectively.

It is also assumed that, in the play list P1, the track (program) #2 hasbeen designated as the play item number PIN #1. It is similarly assumedthat, as the play item numbers PIN #1, the track #3, track #4, track #5and the track #6 are designated in the play list P2, play list P3, playlist P4 and in the play list P5, respectively.

It is also assumed that, in all of the play lists P1 to P5, theselection list S1 is designated as the next list offset (NL-OF), that isthat, if the reproducing operation for the track designated by therespective play lists comes to a close, the operation is returned to theselection list S1.

In such list structure, if the time of 30 seconds has elapsed at thetime point the selection list S1 is in operation, without the userperforming any operation, one of the play lists P1 to P5 is randomlyselected. The track designated by the selected play list is reproducedand, when the reproduction of the track comes to a close, the operationreverts to the selection list S1. If again the time of 30 seconds haselapsed without the user performing any operation, one of the lay listsP1 to P5 is selected at random.

Taking the list structure as an example, the control operation of thesystem controller 53 during the reproduction of a program (track) isexplained by referring to FIG. 27.

In the playback control operation, the system controller 53 judges atstep F101 whether the list is the selection list S1. If the result ofjudgment is YES, the system controller transfers to step F102 and, ifotherwise, the system controller transfers to step F115.

At step F102, the system controller 53 performs reproduction based uponthe play item number (PIN) of the selection list, before transferring tostep F103. Specifically, in the example of FIG. 26, the play item numberPIN of the selection list S1 is 1000. The system controller 53 thencauses the segment play item #1 to be reproduced and displays the menuhaving five alternatives to be displayed as shown in FIG. 26.

At step F103, the system controller 53 judges whether timeout isdesignated in the selection list S1. If the result of judgement is YES,the system controller transfers to step F105 and, if otherwise, thesystem controller transfers to step F114. Specifically, if the value ofthe wait time (W-TO) until timeout is FFh, timeout designation is notmade. Thus the system controller 53 transfers to step F114 and is at astand-by state until a selection operation is performed by the user.That is, the menu is continued to be displayed until an input is made bythe user. If the user performs the selecting operation at step F114, thesystem controller 53 transfers to step F115 and performs the reproducingoperation responsive to the selected play list or to the lower-layerselection list.

On the other hand, if the value of the wait time until timeout in theselection list S1 is 01h to FEh, timeout designation is made, so thatthe system controller 53 transfers to step F105. In the example of FIG.26, the time of 30 seconds is set in the selection list S1.

At step F105, the system controller 53 has e.g., an internal timer, andcompares the timer value and the wait time value to each other to judgewhether or not the timeout is reached. If the result of judgment is YES,the system controller transfers to step F106 and, if otherwise, to stepF113.

At step F113, the system controller 53 judges whether or not the userhas made the selecting operation. If the result of judgment is YES, thesystem controller transfers to step F115 and, if otherwise, the systemcontroller reverts to step F105. Specifically, if the user selects thealternative 2 before the time of 30 seconds has elapsed, the systemcontroller 53 transfers to step F115 for carrying out the list contents.That is, the system controller 53 transfers to the play list P2 by thealternative 2, that is Se1#2, and executes reproduction of the track #3designated as PIN #1.

Conversely, if no operation is done at step F105 until timeout, thesystem controller 53 judges whether or not random designation has beenmade. If the result of judgement is YES, the system controller transfersto step F107 and, if otherwise, the system controller transfers to stepF115. Specifically, if the timeout list offset (TL-OF) is FFFh, randomdesignation is made. Meanwhile, if the list set as timeout list offset(TL-OF) is designated, the designation is not random designation. Thesystem controller 53 transfers to step F115 in order to execute thereproducing operation by the designated list. In the example of FIG. 26,random designation has been made.

At step F107, the system controller 53 confirms the bit map for randomdesignation as to the selection list S1 before transferring to stepF108. The bit map for random designation is such a bit map which thesystem controller 53 forms and holds in the RAM 53a. Specifically, thesystem controller 53 provides an area in which to store the list ID inthe RAM 53a, as shown for example in FIG. 28A. The system controllerthen provides an area of 1 bit associated with Se1#1 to Se1#99. That is,the system controller 53 provides an area for 99 bits corresponding tothe number of alternatives that can be set in the selection list. Thisarea can be constituted by a 13-byte area. The system controller 53forms a bit map in association with a selection list.

At step F108, the system controller 53 judges whether or not the bit mapfor random designation, to which is appended the list ID of the currentselection list, is stored in the RAM 53a. If the result of judgment isYES, the system controller transfers to step F109. If otherwise, that isif the system controller has not transferred in the past in the courseof the operation concerning the selection list to the processingdownstream of the step F107, the system controller 53 transfers to stepF110.

At step F110, the system controller 53 provides a bit map for randomdesignation in the RAM 53a and subsequently initializes the bit map forrandom designation. The system controller then transfers to step F111.Specifically, the system controller 53 provides an area in the RAM 53a,as shown for example in FIG. 28A, and performs initialization forsetting the bit associated with the stored alternative to 1. In theselection list S1 of FIG. 26, since Se1#1 to Se1#5 are present asalternatives, the five bits corresponding thereto are set to 1, as shownfor example in FIG. 28B, by way of initializing the bit map for randomdesignation. The bit map for random designation may also be stored inthe RAM 54.

At step F111, the system controller 53 randomly selects one of the bitsin the bit map for random designation set to 1, before transferring tostep F112. Specifically, the system controller 53 randomly selects analternative from among Se1#1 to Se1#5, using a numerical figuregenerated by a M-series generator or a random generator.

At step F112, the system controller 53 sets the bit for the selectedalternative to 0, before transferring to step F115. At this step F115,the system controller 53 executes the list contents corresponding to thealternative.

If Se1#2, for example, is selected at step F111, the bit correspondingto Se1#2 is set to 0 at step F112, as shown for example in FIG. 28C.Then, at step F115, the contents of the play list P2, that is thereproduction of the track #3, is carried out.

If the reproduction of the track #3, that is the contents of the playlist P2, comes to a close, the system controller 53 reverts to theselection list S1, in the example of FIG. 26, that is transfers fromstep F101 to step F102, for displaying the menu.

If the user does not perform any selecting operation, the systemcontroller 53 transfers to step F107 after lapse of 30 seconds. In suchcase, there is already stored in the RAM 53a the bit map for randomdesignation associated with the selection list S1. Thus the systemcontroller 53 transfers from step F108 to step F109.

At step F109, the system controller 53 judges whether or not allalternatives have been selected in the random designating operation inthe past. If the result of judgment is YES, the system controllertransfers to step F111 and, if otherwise, the system controllertransfers to step F110. Specifically, since the bits associated with theselected bits are set to 0, the system controller judges whether or notall bits of from Se1#1 to Se1#99 of the bit map for random designationare zero. If only the bit associated with Se1#2 is zero, as shown forexample in FIG. 28C, only Se1#2 has been selected in the past, so thatthe system controller 53 transfers to step F111. At step F111, thesystem controller 53 performs random selection of Se1#1 based upon thebit map for random designation. Specifically, the system controller 53selects one alternative from among the alternatives whose bits are 1.That is, in the case shown in FIG. 28C, the system controller 53eliminates Se1#2 and selects Se1#1.

If Se1#4 is selected at step F111, the bit associated with Se1#4 is setto 0 (step F112). The track #5 is then reproduced by the play list P4(step F1F115).

The same holds for the subsequent operations, that is, if the randomselection operation is executed for the selection list S1, randomselection is made from among alternatives whose bits in the bit map forrandom selection at this time point are "1".

At the time point when selection has been made through Se1#1 to Se1#5 bythe random selection operation, the state of bit map for randomselection is such that all bits are 0 as shown for example in FIG. 28E.If the processing in the system controller 53 transfers in this state tostep F108 ff., processing proceeds from step F109 to F110 whereinitialization again is performed. That is, the state of the bit map forrandom designation is that shown in FIG. 28B. The processing at stepsF111 proceeds in a similar manner.

With the instant embodiment, if random selection is performed in a givenselection list, the state of past selection is stored by the bit map forrandom selection, and selection is made from among the unselectedprograms, so that it becomes possible to prohibit the same contents frombeing selected repeatedly.

If the bit map for random selection is stored in the RAM 53a, therespective lists may be ubiquitously selected by random selection duringthe time interval which elapses since the power up until power down. Inaddition, if the bit map for random selection is stored in the RAM 54,the state of past selection may be confirmed for selection withoutregard to the power on/off.

The present invention is not limited to the above-described embodiments,but may be employed in a variety of reproducing devices. The processingexample is also not limited to that shown in FIG. 27. For example, thestep F103 of judging as to presence or absence of timeout designationand the step F105 of timeout judgment may be omitted from FIG. 27 sothat it is judged only whether or not random designation has been made.

INDUSTRIAL APPLICABILITY

It will be seen from the foregoing that, when reproducing the programfrom a recording medium having a plurality of programs recorded thereinand a management area in which alternatives for selecting the programsin reproducing the programs are recorded as the managementalinformation, there is previously recorded an identifier for determiningthe program reproducing mode in the managemental area of the recordingmedium. This managemental information is reproduced from themanagemental area and the reproducing mode is identified based upon theidentifier contained in the managemental information. If the reproducingmode is judged to be the random reproduction, the alternatives areselected based upon the generated random number and the programcorresponding to the selected alternative is reproduced by way ofperforming automatic random reproduction.

Also, according to the present invention, when reproducing the programfrom the recording medium having the program area having plural programsrecorded therein and the managemental area having recorded thereinprogram selecting alternatives for program selection in reproducing theprogram, an identifier for determining the program reproducing mode andthe limit time are previously recorded in the managemental area of therecording medium, and the managemental information is reproduced fromthe managemental area. The limit time contained in the managementalinformation is compared to the count value in a counter. If the countvalue exceeds the limit time, the reproducing mode is judged based uponthe identifier contained in the managemental information. If thereproducing mode is judged to be random reproduction, the alternativeselection is made based upon the generated random number, and theprogram corresponding to the selected alternative is reproduced forautomatically performing random reproduction.

I claim:
 1. A reproducing apparatus for reproducing data from arecording medium, said recording medium having a program area includinga plurality of programs recorded therein and a management area includingmanagement information recorded therein, said management informationincluding a plurality of selection alternatives and a mode identifier,each said selection alternative specifying reproduction of at least oneof said programs, and said mode identifier specifying the mode ofprogram reproduction, said apparatus comprising:reproducing means forreproducing at least one of said programs from the program area of saidrecording medium and for reproducing at least a portion of saidmanagement information from said management area, said reproducedportion including said mode identifier; judgment means for judging themode of program reproduction based upon said reproduced mode identifier;random number generating means for generating a random number; selectionmeans for selecting one of said selection alternatives based upon saidrandom number if the mode of program reproduction judged by saidjudgement means is random reproduction; and control means forcontrolling the reproducing means to reproduce at least one programspecified by the selection alternative selected by said selection means.2. A reproducing apparatus for reproducing data from a recording mediumsaid recording medium having a program area including a plurality ofprograms recorded therein and a management area including managementinformation recorded therein, said management information including aplurality of selection alternatives, a mode identifier and a time limit,each said selection alternative specifying reproduction of at least oneof said programs, and said mode identifier specifying the mode ofprogram reproduction, said apparatus comprising:reproducing means forreproducing at least one of said programs from the program area of saidrecording medium and for reproducing at least a portion of saidmanagement information from said management area, said reproducedportion including said mode identifier and said time limit; timemeasurement means for measuring a period of time prior to saidreproducing of at least one of said programs; judgment means for judgingthe mode of program reproduction based upon said reproduced modeidentifier when said time period exceeds said time limit; random numbergenerating means for generating a random number; selection means forselecting one of said selection alternatives based upon said randomnumber if the mode of program reproduction judged by said judgementmeans is random reproduction; and control means for controlling thereproducing means to reproduce at least one program specified by theselection alternative selected by said selection means.
 3. Thereproducing apparatus as claimed in claim 2 wherein said selection meansincludes storage means for storing an indication of said selected one ofsaid selection alternatives, and wherein, when performing repeatedselections based upon the random number a selection alternative otherthan one of the selection alternatives indicated in the storage means isselected.
 4. A reproducing method for reproducing data from a recordingmedium, said recording medium having a program area including aplurality of programs recorded therein and a management area includingmanagement information recorded therein, said management informationincluding a plurality of selection alternatives and a mode identifier,each said selection alternative specifying reproduction of at least oneof said programs, and said mode identifier specifying the mode ofprogram reproduction, said method comprising the steps of:reproducing atleast a portion of said management information from said managementarea, said reproduced portion including said mode identifier, andjudging the mode of program reproduction based upon said reproduced modeidentifier; selecting one of said selection alternatives based upon agenerated random number if the mode of program reproduction is judged tobe a random reproduction in said judgment step; and reproducing at leastone program specified by said selection alternative selected in saidselecting step.
 5. A reproducing method for reproducing data from arecording medium, said recording medium having a program area includinga plurality of programs recorded therein and a management area includingmanagement information recorded therein, said management informationincluding a plurality of selection alternatives, a mode identifier and atime limit, each said selection alternative specifying reproduction ofat least one of said programs, and said mode identifier specifying themode of program reproduction, said method comprising the stepsof:reproducing at least a portion of said management information fromsaid management area, said reproduced portion including said modeidentifier and said time limit, and comparing said time limit to a countvalue of a counter; judging the mode of program reproduction based uponsaid mode identifier if said count value exceeds said time limit;selecting one of said selection alternatives based upon a generatedrandom number if the mode of program reproduction is judged to be arandom reproduction in said judgment step; and reproducing at least oneprogram specified by said selection alternative selected in saidselecting step.
 6. The reproducing method as claimed in claim 5, furthercomprising the step of storing an indication of said selected one ofsaid selection alternatives in a storage means; and wherein, whenperforming repeated selections based upon said random number a selectionalternative other than one of the selection alternatives indicated inthe storage means is selected.
 7. A recording medium having a programarea including a plurality of programs recorded therein, and amanagement area including management information recorded therein,wherein said management information includes a mode identifier foridentifying whether continuous reproduction or random reproduction basedupon random numbers is to be performed by way of program reproduction.8. The recording medium as claimed in claim 7 wherein said managementinformation includes a time limit which compared to a period of timepreceding reproduction of at least one of said programs, said randomreproduction being performed in accordance with said identifier whensaid time period exceeds said time limit.
 9. A recording medium having aprogram area including a plurality of programs recorded therein, and amanagement area including management information recorded therein, saidmanagement information including a mode identifier for identifyingwhether continuous reproduction or random reproduction based upon randomnumbers is to be performed by way of program reproduction, and saidmanagement information further including a time limit which is comparedto a period of time preceding reproduction of at least one of saidprograms, wherein said random reproduction is performed in accordancewith said mode identifier when said time period exceeds said time limit.